Rear mounted integrated rotary encoder including a pushbutton switch

Abstract

A rear-mount integrated rotary encoder comprises a mechanical portion and a printed circuit board portion. The mechanical portion of a rear mount integrated rotary encoder comprises a housing including a bushing for receiving one end of a rotatable shaft. The rotatable shaft passes through an open front portion of the housing and is mechanically connected to exposed rotatable circuit contacting members. The printed circuit board portion has an encoder contact pattern formed thereon. The printed circuit board has an area larger than the cross sectional area of the housing. The encoder contact pattern surrounds (or is at least concentric with respect to) an aperture in the circuit board. The rotatable shaft of the rotary encoder is passed through the aperture such that the rotatable circuit contacting members contact the encoder contact pattern on the circuit board. An elastomeric button is mounted on the front surface of the circuit board and surrounds the shaft of the rotary encoder to provide a spring-like action. The rotatable shaft is keyed to allow movement orthogonal to the plane of the circuit board while preventing rotation of the knob with respect to the rotatable shaft. When the knob is pressed, the elastomeric button is compressed and a pair of switch contacts, mounted below the elastomeric button, contact each other. In one embodiment, the housing includes projections, substantially orthogonal to the circuit board, for engaging a feature of the circuit board for securing the integrated encoder in an assembled state. In another embodiment of the invention, the housing is attached to the circuit board by means of an adhesive applied to the front surface of the housing. A further feature of the subject rear-mount integrated rotary encoder including a pushbutton switch is that it is substantially cylindrical in shape to reduce the required spacing between adjacent encoders.

what is claimed is:  
     
       1. A mechanical portion of a rear-mount integrated rotary encoder for use with a circuit board having an encoder contact pattern formed thereon, comprising: 
       a housing having a rear surface, a side surface, and a substantially open front area;  
       a rotatable shaft extending substantially orthogonally through said open front area of said housing;  
       a rotatable circuit contacting member mechanically connected to said shaft; and  
       a securing device for securing said mechanical portion to said circuit board;  
       said rotatable shaft being passed through an aperture in said circuit board such that said rotatable circuit contacting member contacts said encoder contact pattern;  
       a knob mounted to said shaft for rotating said shaft;  
       an elastomeric button having an aperture for receiving said shaft, said elastomeric button being mounted between said circuit board and said knob, and when so mounted exerting a force against an underside of said knob; and  
       a pair of switch contacts mounted between an underside of said elastomeric button and said circuit board;  
       said switch contacts being changed between an open state and a closed state by sliding said knob along said shaft.  
     
     
       2. The mechanical portion of the rear-mount integrated rotary encoder of  claim 1  wherein, 
       said shaft includes a keyway and said knob includes a chamber and a key extending into said chamber; and  
       when assembled said key slidably engages said keyway.  
     
     
       3. The mechanical portion of the rear-mount integrated rotary encoder of  claim 2  wherein: 
       said knob includes a shelf portion extending horizontally across a portion of said chamber;  
       said shaft includes a lip portion; and  
       when said knob is pressed onto said shaft, said shelf portion and said lip portion engage to lock said knob to said shaft.  
     
     
       4. The mechanical portion of the rear-mount integrated rotary encoder of  claim 3  wherein: 
       one of said switch contacts is mounted on said underside of said elastomeric button and the other of said switch contacts is mounted to said circuit board.  
     
     
       5. The mechanical portion of the rear-mount integrated rotary encoder of  claim 4  wherein: 
       said securing device is at least one mounting stake formed on said housing, and extending beyond said front area of said housing for engaging a mounting aperture of said circuit board.  
     
     
       6. The mechanical portion of the rear-mount integrated rotary encoder of  claim 5  wherein, 
       said at least one mounting stake is a heat stake, for deforming upon application of heat after insertion into said mounting aperture of said circuit board.  
     
     
       7. The mechanical portion of the rear-mount integrated rotary encoder of  claim 5  wherein, 
       said at least one mounting stake is a cold stake, for deforming upon application of pressure after insertion into said mounting aperture of said circuit board.  
     
     
       8. The mechanical portion of the rear-mount integrated rotary encoder of  claim 5  wherein, 
       said at least one mounting stake is a snap-in stake, for momentarily deforming upon insertion into said mounting aperture of said circuit board.  
     
     
       9. The mechanical portion of the rear-mount integrated rotary encoder of  claim 5  wherein, 
       said housing is substantially cylindrical in shape and said at least one mounting stake is mounted on an outer circumference of said housing.  
     
     
       10. The mechanical portion of the rear-mount integrated rotary encoder of  claim 4  wherein, 
       said securing device is at least one mounting surface formed on said housing at said front area of said housing for engaging a surface of said circuit board and bonding to said circuit board by chemical adhesive means.  
     
     
       11. The mechanical portion of the rear-mount integrated rotary encoder of  claim 4  further including, 
       a detent device mounted on said shaft and engaging a feature of said housing.  
     
     
       12. A rear-mount integrated rotary encoder, comprising: 
       a mechanical portion; and  
       a circuit board portion having an aperture formed therein;  
       said mechanical portion including:  
       a housing having a rear surface, a side surface, and a substantially open front area;  
       a shaft extending substantially orthogonally through said open front area of said housing;  
       rotatable circuit contacting members mechanically connected to said shaft; and  
       a securing device for securing said mechanical portion to said circuit board;  
       said circuit board portion having an area larger than a cross sectional area of said housing, and having an encoder contact pattern formed thereon;  
       said encoder contact pattern being concentric with respect to said aperture in said circuit board;  
       said rotatable shaft being passed through said aperture such that said rotatable circuit contacting members contact said encoder contact pattern on said circuit board;  
       a knob mounted to said shaft for rotating said shaft;  
       an elastomeric button having an aperture for receiving said shaft, said elastomeric button mounted between said circuit board and said knob, and when so mounted exerting a force against an underside of said knob; and  
       a pair of switch contacts mounted between an underside of said elastomeric button, and said circuit board;  
       said switch contacts being changed between an open state and a closed state by sliding said knob along said shaft.  
     
     
       13. The rear-mount integrated rotary encoder of  claim 12  wherein, 
       wherein,  
       said shaft includes a keyway and said knob includes a chamber and a key extending into said chamber; and  
       said key slidably engages said keyway.  
     
     
       14. The rear-mount integrated rotary encoder of  claim 13  wherein: 
       said knob includes a shelf portion extending horizontally across a portion of said chamber;  
       said shaft includes a lip portion; and  
       said knob is pressed onto said shaft, such that said shelf portion and said lip portion engage to lock said knob to said shaft.  
     
     
       15. The rear-mount integrated rotary encoder of  claim 14  wherein: 
       one of said switch contacts is mounted on said underside of said elastomeric button and the other of said switch contacts is mounted to said circuit board.  
     
     
       16. The rear-mount integrated rotary encoder of  claim 15  wherein, 
       said securing device includes projections mounted on said housing and substantially orthogonal to the circuit board, for engaging a feature of the circuit board for securing the integrated encoder in an assembled state.  
     
     
       17. The rear-mount integrated rotary encoder of  claim 16  wherein, 
       said projections are mounting stakes formed on said housing, and extending beyond said front area of said housing.  
     
     
       18. The rear-mount integrated rotary encoder of  claim 17  wherein, 
       said mounting stakes are heat stakes, for deforming upon application of heat after insertion into said mounting aperture of said circuit board.  
     
     
       19. The rear-mount integrated rotary encoder of  claim 17  wherein, 
       said mounting stakes are cold stakes, for deforming upon application of pressure after insertion into said mounting aperture of said circuit board.  
     
     
       20. The rear-mount integrated rotary encoder of  claim 17  wherein, 
       said mounting stakes are snap-in stakes, for momentarily deforming upon insertion into said mounting aperture of said circuit board.  
     
     
       21. The rear-mount integrated rotary encoder of  claim 16  wherein, 
       said housing is substantially cylindrical in shape and said projections are mounted on the outer circumference of said housing.  
     
     
       22. The rear-mount integrated rotary encoder of  claim 15  wherein, 
       said securing device is at least one mounting surface formed on said housing at said front area of said housing for engaging a surface of said circuit board and bonding to said circuit board by chemical adhesive means.  
     
     
       23. The rear-mount integrated rotary encoder of  claim 15  further including, 
       a detent device mounted on said shaft and engaging a feature of said housing.